Why are eink screens so gray?

[JSWolf]

Originally Posted by Renaldo

Just because she hasn't killed and eaten you yet, doesn't mean she's not going to.

She can't do that as it would invalidate my life insurance and she would not get her money.

[snipenekkid]

lilac_jive, you just can't help yourself. It is great you have such enthusiasm for your device. I think the technology is certainly heading in the correct direction. Still I feel in short order there will be a significant improvement. Hopefully via competition as more players come to market. Still, I think you missed or forgot where I mentioned I tied the Sony 505 in person. And if I failed to mention that early on, I at least thought I wanted to mention it. You might read my first few comments if that matters. But, no I am not going to buy an eink device anytime in the next few months unless there is a sudden improvement in the contrast ratio and white reflectivity of the displays. Still that was not my original question. I wanted to understand why the displays are so grey not debate if they are good enough to read on or not.

[sammsmom]

Honestly the gray does not bother me. I was expecting something like a white screen when I purchased my 505 but I was pleasantly surprised by the screen. I feel that it is amazingly easy on the eyes and allows me to read for hour on end unlike looking at a white computer screen which eventually hurts my eyes.

[snipenekkid]

Originally Posted by lilac_jive

I'm not trying to debate, I was serious. I was of course concerned when you said some ebook makers were potentially photoshopping pictures of devices.

while there is nothing wrong with cleaning up a photo of a device. Marketing can be a tad eager trying to make an impression. Here is one example I just ran across shown right in this forum in the first post.

https://www.mobileread.com/forums/att...7&d=1236329874

here is the tread https://www.mobileread.com/forums/sho...25&postcount=1

If you examine the EXIF on the first image, you can see it was edited in Photoshop, CS3 to be exact. There were two likely reasons for this. First the white balance of the shot was off because the image was not correctly lighted and or exposed. While correcting that white balance could inadvertently changed the display, I doubt it. More likely is the 2nd reason was to enhance the whiteness of the display.

I am not going to hold BeBook as the only company guilty of such misrepresentation as I know I have found other examples during the course of my research.

Unfortunately the EXIF on the BeBook image is a minimal detail level so there is no information about the original exposure and what sort of white balance adjustment was performed in post processing. I do feel this was intentional not an innocent action.

[Alisa]

I'm going to be completely scandalous and admit that I would prefer if the screen were whiter. There. I said it. I do find lighting conditions make a HUGE difference. Sadly, being a bit of an EcoGeek, my lamps all have CFL bulbs which really don't help. My LED booklight is probably the best condition I get in my house. Still, I find reading on e-ink to be quite nice. I've been doing it for a year and only read paper if I absolutely must. I find the trade-offs attractive enough that I'm willing to jump in at this early phase of immature technology and inflated prices.

[HarryT]

Originally Posted by snipenekkid

Still I feel in short order there will be a significant improvement. Hopefully via competition as more players come to market.

Not necessarily. Remember that, although there are a lot of different devices on the market, there is only one manufacturer of eInk screens - PVI in Taiwan. All the 6" eInk devices use the same screen, as in "made on the same production line in the same factory". There is only one screen out there!

[snipenekkid]

HarryT do you comment on every thread on the site? When are you able to actually read?

[Jellby]

In my screen I noticed that not only the "white" is not white, but it's not uniform, it has some tiny black spots all over the place (smaller than a pixel size).

In the attached picture you can see a close-up of what I assume is a normal e-ink screen, there you can see that even if the particles were pure white, there is still some "background" showing up (and some white in the black too).

[HarryT]

Originally Posted by Jellby

In my screen I noticed that not only the "white" is not white, but it's not uniform, it has some tiny black spots all over the place (smaller than a pixel size).

That's perfectly normal - there was a long discussion of it recently in the Hanlin forum. The consensus of opinion is that it's because not all the particles in the pixel cell "flip" to the appropriate state; if they are told to "flip to white", a small percentage of them stay "black", and vice versa.

[snipenekkid]

very nice find Jellby. I was wondering earlier if the shape of the particles which are depicted as spherical in illustrations would create a gap as round does not allow for a compact fit. So maybe the answer will ultimately be a change in geometry of the particles used. Though those look to be hexagonal which should be able to compact fairly close. But there are certainly black gaps. Maybe this combined with the actual opacity of the particles is the key.

I wonder how many layers thick the particles are arranged. No matter I think your photo of the display really does show the root cause. That should be fixable in not too long a period. Heck I wonder how many shapes the engineers when through before settling on the quasi-spherical particles?

[Jellby]

I don't think they can control the shape of the particles, they look like cells or bubbles, mainly spherical but tending to hexagonal when they are closely packed. The walls are probably not rigid either.

[aapezzuto]

Come on guys, this is effectively a really nice magni-doodle! The physics are almost the same, but the scale is smaller. because of the smaller scale, when the black particles are removed from the front plane they are not far enough away from a frosted surface to be unnoticed, so they had to have an opposite particle that would rise to the surface... It would not surprise me at all to find out that either the "black" or the "white" particles are not polarized at all, and they just switch to the proper state because of spacial restraints... sort of like a milky oil with a bunch of iron dust.

the 16 levels greyscale has to do with the magnetics and controllers.... I imagine also that the improved screens on the 505 vs the 500 have a slightly improved "fluid" in the individual cells. This would explain the 5-10% improved contrast.

It is certain that this or a similar technology will get better. It has been made clear that the screen is not white, and neither is a normal mass market paperback, newspaper, etc...

To get back to the original question of why they are so grey... because they are a semi mechanical device that has a mixture of light grey and dark grey particles, that across significant use get even more mixed... most things that are "white" are more like reflective with strong diffusion... and nothing is black. Try finding a good white ink... Most decent oil painters still go back to the old lead oxide. House paint had to move away from that a while ago, and I dobt anyone wants it in our e-ink devices.

[dmaul1114]

Originally Posted by sammsmom

Honestly the gray does not bother me. I was expecting something like a white screen when I purchased my 505 but I was pleasantly surprised by the screen. I feel that it is amazingly easy on the eyes and allows me to read for hour on end unlike looking at a white computer screen which eventually hurts my eyes.

Agreed. I'm the same with physical reading materials. Stuff on a bright white page (like say Newsweek and other mags) gets my eyes tired much faster than a grayer paper like a newspaper or some paperbacks.

As for why e-ink screens are grey, I have no idea whether it was done deliberately to reduce eyestrain or if that's just the limitation of the technology. i.e. maybe it's hard to have a white screen that's not backlit or LCD etc. currently?

[pshrynk]

Originally Posted by snipenekkid

My interest in them was peaked when viewing the marketing photo's showing very white backgrounds on the devices. After viewing the Sony devices in person I now see those photo's were either photoshop enhanced or taken under extremely bright lighting conditions with studio strobes or speedlights to enhance the contrast enough to make the image appear to have a white background.

The temperature of a speedlight or a studio strobe is quite high and will wash out 20% gray. In fact, they are calibrated using a 20% as "white" and therefore the ads will make them look white in the background. Making a photo look exactly like real life is nearly impossible. Bringing the background back up to 20% gray will, in fact muddy the entire picture up to the point that it looks like crap. As, you've said, you have looked at a Sony, and have seen the actual irl product.

I can only say that from my experience, the 20% gray background tends to just fade away after you have used the device for long enough. With the new Kindle 2, there have been some complaints aobut the level of contrast with the words, which can ceratinly be annoying. I haven't noticed any problems with mine, however.

[pilotbob]

Originally Posted by HarryT

Not necessarily. Remember that, although there are a lot of different devices on the market, there is only one manufacturer of eInk screens - PVI in Taiwan. All the 6" eInk devices use the same screen, as in "made on the same production line in the same factory". There is only one screen out there!

That is true of devices 'on the market' but I think there are some other competitors in the pipe line. Plastic Logic is one. I recall some others. One using electrowetting or something too.

BOb